System and method for monitoring a fiber and a detector attached to the fiber

ABSTRACT

A system for detecting an intrusion of at least one of a monitoring fiber and a detector comprises a sensor having a closure monitor and an intrusion monitor, the closure monitor including a signal generator and at least one detector attached to the monitoring fiber. The signal generator transmits signal light such that the monitoring fiber receives the transmitted signal light and reflects a portion of the signal light via the at least one detector to the closure monitor and transmits a non-reflected portion of the signal light. The intrusion monitor receives the transmitted non-reflected portion of the signal light, and monitors the non-reflected portion of the signal light to detect transient changes in the non-reflected portion of the signal light indicative of at least one of a vibration, a motion and a handling of at least one of the monitoring fiber and the at least one detector.

CROSS-REFERENCE TO RELATED PATENTS AND PATENT APPLICATIONS

This application relates to a system for detecting an intrusion of atleast one of a monitoring fiber and at least one detector (e.g. a fiberoptic manhole) attached to the monitoring fiber. Specifically, theapplication relates to monitoring a non-reflected portion of signallight to detect transient changes in the non-reflected portion of thesignal light indicative of at least one of a vibration, a motion and ahandling of at least one of the monitoring fiber and the at least onedetector.

The application incorporates by reference the contents of each of U.S.Pat. Nos. 7,092,586; 7,120,324; 7,142,737; 7,206,469; 7,333,681;7,403,674; 7,403,675; 7,634,387; 7,693,359; 7,706,641; 8,094,977;8,233,755; and 9,046,669 and patent application Nos. 14/144,882;14/145,121; and 14/457,818 which describe fiber optic detectionapparatuses, systems and methods pertaining to monitoring an opticalfiber and an optical fiber communication network that may be employed inthe embodiments disclosed herein.

BACKGROUND

Modernly, data cables are run underground cities, campuses, and otherlocations with a point of access to the data cables being realizedthrough a plurality of manholes having respective covers. Federalregulations may require the manhole covers to be locked or welded shutand/or to be protected by an alarm to detect a physical displacement oropening of the manhole. As threats of industrial espionage and domesticterrorism loom, non-federal entities are developing an enhanced posturetowards data protection at the physical manhole cover layer.

Similarly, data networks within buildings also have protected points ofentry such as doors to lock boxes. Protection mechanisms for manholesare adaptable for the barriers or enclosures for data networks indiscreet facilities (e.g., buildings, warehouses, etc.).

Existing manhole protection systems may use detectors that include, forexample, Fiber Bragg Gratings (FBG) such as those manufactured byCleveland Electric Laboratories and CyberSecure IPS or fiber opticmacrobend based detectors such as those manufactured by WovenElectronics, to detect the opening of a door or lid such as a manholecover or network enclosure.

A system for detecting the physical displacement or opening of a manholecover (i.e. a closure for a secure space or a network enclosure) isreferred to herein as a “manhole” system. However, it should berecognized that the “manhole” system embodiments described herein mayalso be implemented as systems to detect the opening of doors inprotective boxes for network installations, such as the user boxes in aProtective Distribution System.

These manhole systems afford protection for what is encased by thesedoors or covers by alarming when the sensor is actuated. Typically, theprotection is for safeguarding data infrastructure such as networkcables by detection of a potential intruder gaining access to an area ofvulnerability.

A secondary level of protection, also described herein, for those datacables or other infrastructure may be implemented by further protectingand/or monitoring the cables or conveyance(s) against a physicalintrusion such as tapping the cable for data theft or denial of serviceattacks by detection of mechanical perturbations that exist as a preludeto access.

These systems (and methods) that monitor and protect data cables againsta physical intrusion may be referred to as alarmed carrier systems. Asdescribed herein, systems and methods may be implemented that integratethe manhole systems and the alarmed carrier systems together. Thisprotection can be in the form of a sensor that detects handling andvibration of the cable or conveyance, such as by the INTERCEPTOR™ andVANGUARD™ products manufactured by Network Integrity Systems. Thesesystems detect access to the cables carrying data, supplementing thephysical security afforded by the door and manhole sensors.

A current manhole system assumes that any attempted breach into a datacable and/or network will be at a manhole or other sensor point, andwill be detected by the sensor. However, if the breach occurs at alocation anywhere other than at a specific sensor, the breach will notbe detected. A secondary sensor system is a failsafe against anintrusion that is able to defeat (e.g., disable, avoid or bypass) amanhole or door sensor. If a manhole sensor is bypassed, the cable maystill be protected because intrusion can be detected by a cable sensor.

The primary function of a manhole protection system is to prevent anattack on the cable located below the manhole (e.g., in the lock box),this primary function of the system may still be achieved by a cablesensor even if the manhole sensor is defeated. This secondary type ofprotection is particularly valuable in tunnel situations where anattacker might gain access to data cables by digging or tunneling toavoid detection by the door/manhole alarms.

Additionally, the sensors used for door/manhole alarms employ sensorfibers that are typically separate from the data fibers, because thesesensors are installed inline on a fiber at each door/manhole location.The door/manhole sensor system is often an addition to an existinginstallation, and the sensor fiber may be attached to the doors andmanholes. In all of these cases, an additional simple sensing fibermight be added to provide secondary protection.

In typical installations the data cable is of continuous length, andwould not need to be intentionally breached to allow connection to thedoor/manhole alarm. Rather, the data would reside in cable(s) adjacentto but separate from the door/manhole alarm fiber.

Additionally, this secondary protection protects the manhole sensorfiber itself; if someone digs up and enters a cable and finds a way tocut or obscure the manhole sensor cable, all of the manhole sensors fromthat point on will be blind. Use of an Interceptor/Vanguard type sensorwill allow detection of cable tampering before the cable cut and themanhole sensors defeated.

In addition to protecting the sensor and data cables, this secondarysensor system protects the conveyance which houses the data cables. Awould be intruder can be detected upon a breach of any conveyance (i.e.,carrier, conduit, duct, housing, etc.) prior to accessing the datafibers internal to the cables.

In some embodiments, there are several possibilities for the lighttransmitted into the manhole fiber by the manhole monitoring system tobe used by the secondary monitoring system, which must be configured toaccommodate this. In some embodiments, the direction of light travel isarbitrary, and functionality is identical if the direction of light isreversed.

SUMMARY

According to an embodiment, a system for detecting an intrusion of atleast one of a monitoring fiber 30 and a detector 20 comprises a sensor10 having a closure monitor and an intrusion monitor, the closuremonitor including a signal generator; the monitoring fiber having afirst end and a second end; and at least one detector 20 attached to themonitoring fiber. The signal generator generates and transmits signallight and the monitoring fiber receives the transmitted signal light viathe first end of the monitoring fiber and reflects a portion of thesignal light via the at least one detector 20 to the closure monitor.Further, the monitoring fiber 30 transmits a non-reflected portion ofthe signal light via the second end of the monitoring fiber 30. Theintrusion monitor receives the transmitted non-reflected portion of thesignal light, and monitors the non-reflected portion of the signal lightto detect transient changes in the non-reflected portion of the signallight indicative of at least one of a vibration, a motion and a handlingof at least one of the monitoring fiber 30 and the at least one detector20.

The object and advantages of embodiments described herein will berealized and attained by means of the elements and combinationsparticularly pointed out in the claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and arenot restrictive of the embodiments as claimed.

DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates signal light being transmitted to a monitoring fiber30 such that a portion of the signal light is reflected to a closuremonitor by at least one detector 20 attached to the monitoring fiber 30and a non-reflected portion of the signal light is transmitted to anintrusion monitor.

FIG. 2 illustrates the signal light being transmitted to the monitoringfiber 30 and a portion of the signal light being returned by anextrinsic sensor fiber 40.

FIG. 3 illustrates the signal light being transmitted to the monitoringfiber 30 and a portion of the signal light being returned by at leastone unused fiber of a cable 50.

FIG. 4 illustrates the signal light being transmitted to the monitoringfiber 30 and a portion of the signal light being returned by at leastone unused fiber of a plurality of cables 50.

FIG. 5 illustrates the signal light being transmitted to the monitoringfiber 30 and a portion of the signal light being returned extrinsicallyby the at least one sensor fiber 40 and by at least one unused fiber ofa plurality of cables 50.

FIG. 6 illustrates the signal light being transmitted to the monitoringfiber 30 and a portion of the signal light being returned extrinsicallyby the at least one sensor fiber 40 that monitors at least one unusedfiber of a cable 50 located proximate and along the at least one sensorfiber 40.

FIG. 7 illustrates signals from two light transmitters being multiplexedand being transmitted to the monitoring fiber 30.

FIG. 8 illustrates signals from two light transmitters beingmultiplexed, the multiplexed signals being transmitted to the monitoringfiber 30 and a portion of the multiplexed signal light being returnedextrinsically by the at least one sensor fiber 40.

FIG. 9 illustrates signals from two light transmitters beingmultiplexed, the multiplexed signals being transmitted to the monitoringfiber 30 and a portion of the multiplexed signal being returnedintrinsically on an unused fiber within a cable 50 containing aplurality of fibers.

FIG. 10 illustrates signals from two light transmitters beingmultiplexed, the multiplexed signals being transmitted to the monitoringfiber 30 and a portion of the multiplexed signal being returnedintrinsically on an unused fiber of a plurality of cables 50.

FIG. 11 signals from two light transmitters being multiplexed, themultiplexed signals being transmitted to the monitoring fiber 30 and aportion of the multiplexed signal being returned intrinsically by anunused fiber of a plurality of cables 50 and extrinsically by a sensorfiber 40.

FIG. 12 illustrates signal light being transmitted to a monitoring fiber30 such that a portion of the signal light is reflected to a closuremonitor by at least one detector 20 attached to the monitoring fiber anda non-reflected portion of the signal light is transmitted to anintrusion monitor on a data carrying or active fiber of a data cable 50to provide for intrinsic monitoring of the data cable 50.

FIG. 13 illustrates signals from two light transmitters beingmultiplexed, the multiplexed signals being transmitted to the monitoringfiber 30 and a portion of the multiplexed signal light being returned toa closure monitor by at least one detector 20 attached to the monitoringfiber and a non-reflected portion of the signal light is transmitted toan intrusion monitor on a data carrying or active fiber of a data cable50 to provide for intrinsic monitoring of the data cable 50.

DETAILED DESCRIPTION

A “Manhole Monitor System” is the system described above, which uses asfew as a single fiber for the monitoring of opto-mechanical switches onmanhole covers and enclosure doors. When the cover is lifted or the dooris opened, a physical displacement causes a change in characteristics ofthe monitor light (i.e., monitor signal) within the fiber. This allows ahead end device to detect the opening of the protected device, and forsome systems, discernment as to which sensor was activated (e.g. aspecific manhole or specific user box within a particular room).

As referred to herein, “Extrinsic Monitoring” is the protection of adata carrying cable, group of cables, or conveyance by monitoring one ormore sensor fibers placed in close proximity to, or within theconveyance, being protected. This method of extrinsic monitoring cameinto use by manufacturers of fiber optic sensors, typically perimetersecurity systems, which were placed into the conduits and duct banks ofexisting networks. Extrinsic monitoring systems are in compliance to thefederal regulation for an Alarmed Carrier Protective DistributionSystem. Extrinsic monitoring systems typically use vibration or motionas a characteristic of the signal light being monitored.

As referred to herein, “Intrinsic Monitoring” is the protection of adata carrying cable by monitoring one or more fibers within that cable.Typically this is done by injecting a monitor signal into one or moreunused fibers while monitoring exiting signal(s) for indications ofdisturbances. Intrinsic monitoring is similar to extrinsic monitoringexcept that, in intrinsic monitoring, the actual cable being protectedis alarmed, and the closer one gets to the fibers, the more sensitivethe system becomes.

Another form of Intrinsic monitoring involves alarming “active” fibers,that is, fibers currently in use such as for carrying data. Activefibers can be monitored by, at one end of the fiber, multiplexing aseparate, different monitor light or monitor signal with the datasignal(s), and de-multiplexing that monitor signal at the other end,joining and separating the two. FIG. 12 illustrates an exemplaryembodiment of a system for monitoring active fibers in a condition wherethe manhole system signal is compatible with the secondary monitoringsystem and is being used as the monitor signal for both systems. FIG. 13illustrates an exemplary embodiment of a system that monitors an activefiber intrinsically and the manhole signal is not suitable for use withthe secondary monitor. Thus, the system shown in FIG. 13 includes twomonitor signals—one for the manhole system and one for the secondarysystem.

Other systems may use a combination Intrinsic/Extrinsic monitoring.These systems use a combination of both types of monitoring where themonitor signal(s) is(are) routed through both one or more fibersinternal to a cable, as well as one or more fibers external to thecable. This combination allows both sensitive cable monitoring as wellas the added security of monitoring the conveyance for the fibers. Anexemplary embodiment of a system employing a combination of intrinsicand extrinsic monitoring is shown in FIG. 5.

Various exemplary embodiments of the system and method for monitoring afiber and at least one detector attached to the fiber are describedbelow.

According to an exemplary embodiment shown in FIG. 1, a system fordetecting an intrusion of at least one of a monitoring fiber 30 and adetector 20 comprises a sensor 10 having a closure monitor and anintrusion monitor, a monitoring fiber 30 having a first end and a secondend and at least one detector 20 attached to the monitoring fiber.

The closure monitor includes a signal generator that generates andtransmits signal light. The signal generator may be one of a laser, alight emitting diode or other broadband light source and a variablewavelength source (e.g., a swept wavelength laser). The signal light maybe a continuous wave (CW) light of a single or narrow wavelength.Further, the signal light may be chosen to be suitable for transmission(i.e., may be used as the sensing signal) for the chosen secondaryintrusion monitoring system.

The monitoring fiber 30 receives the transmitted signal light via thefirst end of the monitoring fiber and reflects a portion of the signallight via the at least one detector 20 to the closure monitor. Further,the monitoring fiber 30 transmits a non-reflected portion of the signallight via the second end of the monitoring fiber. As mentioned above,the at least one detector may be, for example, a Fiber Bragg Grating(FBG) reflector.

The intrusion monitor receives the transmitted non-reflected portion ofthe signal light, and monitors the non-reflected portion of the signallight to detect transient changes in the non-reflected portion of thesignal light indicative of at least one of a vibration, a motion and ahandling of at least one of the monitoring fiber 30 and the at least onedetector 20.

The signal generator of the closure monitor generates and transmits thesignal light to the monitoring fiber 30 and a portion of the signallight is returned to the intrusion monitor by being looped back on themonitoring fiber 30. Accordingly, the system as shown in FIG. 1 mayprovide intrinsic monitoring of the closure and detector 20 via signallight and a single monitoring fiber 30.

As shown in FIG. 2, in another embodiment the system further comprisesat least one sensor fiber 40 having a first end and a second end. The atleast one sensor fiber 40 receives the transmitted non-reflected portionof the signal light via the first end of the at least one sensor fiberand transmits the non-reflected portion of the signal light via thesecond end of the at least one sensor fiber. The at least one sensorfiber 40 is a separate extrinsic sensor fiber and may be located, forexample, proximate and along a sensor cable.

The intrusion monitor receives the transmitted non-reflected portion ofthe signal light, and monitors the non-reflected portion of the signallight to detect transient changes in the non-reflected portion of thesignal light indicative of at least one of a vibration, a motion and ahandling of at least one of the monitoring fiber 30 and the at least onedetector 20.

The signal generator of the closure monitor generates and transmits thesignal light to the monitoring fiber 30 and a portion of the signallight is returned to the intrusion monitor by being looped back on theat least one sensor fiber 40. Accordingly, the system as shown in FIG. 2may provide extrinsic monitoring via signal light, a single monitoringfiber 30 and at least one sensor fiber 40.

As shown in FIG. 3, in another exemplary embodiment, the system mayfurther comprise at least one unused fiber (i.e. a dark fiber) having afirst end and a second end. The at least one unused fiber does notactively transmit or carry data. The at least one unused fiber receivesthe transmitted non-reflected portion of the signal light via the firstend of the at least one unused fiber and transmits the non-reflectedportion of the signal light via the second end of the at least oneunused fiber.

The intrusion monitor receives the transmitted non-reflected portion ofthe signal light, and monitors the non-reflected portion of the signallight to detect transient changes in the non-reflected portion of thesignal light indicative of at least one of a vibration, a motion and ahandling of at least one of the monitoring fiber 30 and the at least onedetector 20.

The signal generator of the closure monitor generates and transmits thesignal light to the monitoring fiber 30 and a portion of the signallight is returned to the intrusion monitor by being looped back on theat least one unused fiber. Accordingly, the system as shown in FIG. 3may provide intrinsic monitoring of the data cable via signal light, asingle monitoring fiber 30 and at least one unused fiber.

As shown in FIG. 3, in another embodiment, the system further comprisesat least one unused fiber having a first end and a second end. The atleast one unused fiber does not transmit data. The at least one unusedfiber receives the transmitted non-reflected portion of the signal lightvia the first end of the at least one unused fiber and transmits thenon-reflected portion of the signal light via the second end of the atleast one unused fiber. The at least one unused fiber is a fiber among aplurality of fibers of a cable 50.

The intrusion monitor receives the transmitted non-reflected portion ofthe signal light, and monitors the non-reflected portion of the signallight to detect transient changes in the non-reflected portion of thesignal light indicative of at least one of a vibration, a motion and ahandling of at least one of the monitoring fiber 30 and the at least onedetector 20.

Therefore the signal generator of the closure monitor generates andtransmits the signal light to the monitoring fiber 30 and a portion ofthe signal light is returned to the intrusion monitor by being loopedback on the at least one unused fiber. Accordingly, the system as shownin FIG. 3 may provide intrinsic monitoring via signal light, a singlemonitoring fiber 30 and at least one unused fiber.

As shown in FIG. 4, in another embodiment the system further comprisesan unused fiber among a plurality of fibers of a plurality of cables 50respectively having a first end and a second end. The unused fiber doesnot transmit or carry data. The unused fiber receives the transmittednon-reflected portion of the signal light via the first end of theunused fiber and transmits the non-reflected portion of the signal lightvia the second end of the unused fiber. The plurality of fibers arefibers of respective data cables 50.

Therefore, and as shown in FIG. 4, the signal generator of the closuremonitor may be configured to generate and transmits the signal light tothe monitoring fiber 30 and a portion of the signal light is directed tothe intrusion monitor by being looped back on the unused fiber.Accordingly, the system as shown in FIG. 4 may provide intrinsicmonitoring via signal light transmitted through a single monitoringfiber 30 and the unused fiber back to the intrusion monitor.

As shown in FIG. 5, according to another exemplary embodiment, thesystem further may include the least one sensor fiber 40 and a pluralityof unused fibers. However, the system may also comprise the at least onesensor fiber 40 and a single unused fiber.

As shown in FIG. 5, the signal generator of the closure monitorgenerates and transmits the signal light to the monitoring fiber and aportion of the signal light is returned to the intrusion monitor bybeing looped back on the at least one sensor fiber and an unused fiberamong the plurality of fibers. Accordingly, the system as shown in FIG.5 may provide extrinsic monitoring via the at least one sensor fiber 40and intrinsic monitoring via the unused fiber among the plurality offibers.

As shown in FIG. 6, in another exemplary embodiment the system furthercomprises the at least one sensor fiber 40 located proximate and along acable 50.

As shown in FIG. 6, the signal generator of the closure monitorgenerates and transmits the signal light to the monitoring fiber 30 anda portion of the signal light is returned to the intrusion monitor bybeing looped back on the at least one sensor fiber 40. Accordingly, thesystem as shown in FIG. 6 may provide extrinsic monitoring via the atleast one sensor fiber 40 that monitors the at least one unused fiber ofthe data cable 50 thereby alarming the conveyance and protecting thedata cable 50.

According to another exemplary embodiment, the signal light transmittedby the signal generator of the closure monitor may be a light sourcethat is configured to generate light signals that are unsuitable for theintrusion monitor. Therefore, the intrusion monitor must supply anoptical source or signal light that is separate from but generallycompatible with the signal being generated by the closure monitor. Thesignal light provided by the intrusion monitor may be used tointrinsically or extrinsically to monitor for intrusions of a data cable50 and, also, intrinsically and extrinsically monitor the monitoringfiber 30 and detectors 20.

As shown in FIG. 7 and according to the second embodiment, a system fordetecting an intrusion of at least one of a monitoring fiber 30 and/or adetector 20 comprises a sensor having a closure monitor and an intrusionmonitor, a multiplexer, a monitoring fiber having a first end and asecond end and at least one detector 20 attached to the monitoring fiber30.

The closure monitor includes a first signal generator that generates andtransmits a first signal light. The first signal generator may be one ofmultiple continuous wave (CW) light sources such as the spectrum ofwavelengths consistent with dense wavelength division multiplexing(DWDM) and an optical time domain reflectometer (OTDR). The first signallight may be a pulsed signal light.

The intrusion monitor includes a second signal generator that generatesand transmits a second signal light. The second signal generator may beone a laser, a light emitting diode or other broadband light source anda variable wavelength source (e.g., a swept wavelength laser). Thesecond signal light is continuous wave (CW) light of a single or narrowwavelength.

The multiplexer multiplexes the first signal light and the second signallight. The multiplexer may be one of a dense wavelength divisionmultiplexer (DWDM); a filter wavelength division multiplexer (WDM); athin film WDM; a coarse wavelength division multiplexer (CWDM); anadd/drop multiplexer, a polarization controller; and a time divisionmultiplexer (TDM).

The monitoring fiber 30 receives the transmitted multiplexed signallight via the first end of the monitoring fiber and reflects a portionof the multiplexed signal light via the at least one detector 20 to theclosure monitor. Further, the monitoring fiber transmits a non-reflectedportion of the multiplexed signal light via the second end of themonitoring fiber. The at least one detector 20 may be a Fiber BraggGrating (FBG) reflector.

The intrusion monitor receives the transmitted non-reflected portion ofthe multiplexed signal light, and monitors the non-reflected portion ofthe multiplexed signal light to detect transient changes in thenon-reflected portion of the signal light indicative of at least one ofa vibration, a motion and a handling of at least one of the monitoringfiber 30 and the at least one detector 20.

Therefore, the second signal generator of the intrusion monitorgenerates and transmits the second signal light (multiplexed the firstsignal light) to the monitoring fiber 30 and the second signal light isreturned to the intrusion monitor by being looped back on the monitoringfiber 30. Accordingly, the system as shown in FIG. 7 may provideintrinsic monitoring using the intrusion monitor.

The system may provide intrinsic monitoring at the closure monitorbecause the first signal light has specific wavelengths tuned tomultiple end FBG reflectors including those used for a door and/ormanhole lift to determine a location of the door and/or manhole.

The system may also provide intrinsic monitoring for the monitoringfiber 30 with a single fiber alarm system that may include an opticaltime domain reflectometer (OTDR) or polarization optical time domainreflectometer (POTDR) wavelength specific or broadband reflection at thefar end. The system may also intrinsically monitor the monitoring fiber30 (using the intrusion monitor) by selecting a wavelength for the firstsignal light not used and not blocked by an FBG.

As shown in FIG. 8, in another exemplary embodiment, the system furthercomprises at least one sensor fiber 40 having a first end and a secondend. The at least one sensor fiber 40 receives the transmittednon-reflected portion of the multiplexed signal light via the first endof the at least one sensor fiber 40 and transmits the non-reflectedportion of the multiplexed signal light via the second end of the atleast one sensor fiber. The at least one sensor fiber 40 is a separateextrinsic sensor fiber that may be located proximate and along a sensorcable.

The intrusion monitor receives the transmitted non-reflected portion ofthe multiplexed signal light, and monitors the non-reflected portion ofthe multiplexed signal light to detect transient changes in thenon-reflected portion of the signal light indicative of at least one ofa vibration, a motion and a handling of at least one of the monitoringfiber 30 and the at least one detector 20.

The first signal light and the second signal light is multiplexed andtransmitted to the monitoring fiber and a portion of the multiplexedsignal light is returned to the intrusion monitor by being looped backon the at least one sensor fiber 40. Accordingly, the system as shown inFIG. 8 may provide extrinsic monitoring of the data or sensor cable.

As shown in FIG. 9, in another embodiment the system further comprisesat least one unused fiber (i.e. a dark fiber) among a plurality offibers of a cable 50. The unused fiber has a first end and a second end.The at least one unused fiber does not actively transmit data. The atleast one unused fiber receives the transmitted non-reflected portion ofthe multiplexed signal light via the first end of the at least oneunused fiber and transmits the non-reflected portion of the multiplexedsignal light via the second end of the at least one unused fiber.

The intrusion monitor receives the transmitted non-reflected portion ofthe multiplexed signal light, and monitors the non-reflected portion ofthe multiplexed signal light to detect transient changes in thenon-reflected portion of the signal light indicative of at least one ofa vibration, a motion and a handling of at least one of the monitoringfiber 30 and the at least one detector 20.

Therefore, the first signal light and the second signal light aremultiplexed and transmitted to the monitoring fiber 30 and a portion ofthe multiplexed signal light is returned to the intrusion monitor bybeing looped back on the at least one unused fiber. Accordingly, thesystem as shown in FIG. 9 may provide intrinsic monitoring of the cablecontaining the dark fiber.

As shown in FIG. 10, in another embodiment, the system further mayinclude a plurality of unused fibers respectively each having a firstend and a second end. The plurality of unused fibers do not respectivelytransmit data. The plurality of unused fibers receive the transmittednon-reflected portion of the multiplexed signal light via the respectivefirst ends of the plurality of unused fibers and transmit thenon-reflected portion of the multiplexed signal light via the respectivesecond ends of the plurality of unused fibers. The plurality of unusedfibers are fibers of respective data cables 50.

The first signal light and the second signal light are multiplexed andtransmitted to the monitoring fiber 30 and a portion of the multiplexedsignal light is returned to the intrusion monitor by being looped backon the plurality of unused fibers. Accordingly, the system as shown inFIG. 10 may provide intrinsic monitoring of multiple cables 50 via theunused fibers contained in the cables 50.

As shown in FIG. 11, in another embodiment the system further comprisesthe least one sensor fiber 40 and a plurality of unused fibers. However,the system may also comprise the at least one sensor fiber 40 and asingle unused fiber.

As shown in FIG. 11, the first signal light and the second signal lightare multiplexed and transmitted to the monitoring fiber and a portion ofthe multiplexed signal light is returned to the intrusion monitor bybeing looped back on the at least one sensor fiber 40 and the pluralityof unused fibers. Accordingly, the system as shown in FIG. 11 mayprovide extrinsic monitoring of the monitoring and sensor fibers 40 andintrinsic monitoring of the cables 50 carrying unused fibers.

As shown in FIG. 12, a system for detecting an intrusion of at least oneof a monitoring fiber 30 and a detector 20 includes a closure monitorand an intrusion monitor. The monitoring fiber 30 has a first end and asecond end and at least one detector 20 is attached to the monitoringfiber 30. The system may also include a data device, a multiplexer, anda demultiplexer. The closure monitor includes a first signal generatorand the second data device includes a second signal generator.

The first signal generator of the closure monitor generates andtransmits a first signal light having, for example, a first wavelength.The monitoring fiber 30 receives the transmitted first signal light viathe first end of the monitoring fiber and reflects a portion of thefirst signal light via the at least one detector 20 back to the closuremonitor. Further, the monitoring fiber 30 transmits a non-reflectedportion of the first signal light via the second end of the monitoringfiber.

The signal generator of the data device generates and transmits secondsignal light having a second wavelength. As shown in FIG. 12, there maybe two or more data devices exchanging data along the bi-directionalactive fiber. The multiplexer multiplexes the non-reflected portion ofthe first signal light and the second data carrying signal light. Thebi-directional active fiber receives the transmitted multiplexed signallight via the first end of the active fiber and transmits themultiplexed signal light via the second end of the active fiber.

The demultiplexer separates the non-reflected portion of the firstsignal light having a first wavelength and the second signal lighthaving a second wavelength. Accordingly, the intrusion monitor receivesthe transmitted non-reflected portion of the first signal light. Inaddition, the intrusion monitor monitors the non-reflected portion ofthe first signal light to detect transient changes in the non-reflectedportion of the multiplexed signal light indicative of at least one of avibration, a motion and a handling of at least one of the monitoringfiber 30 and the at least one detector 20. The intrusion monitor mayalso provide for intrinsic monitoring of the cable carrying the activefiber.

As shown in FIG. 13, a system for detecting an intrusion of at least oneof a monitoring fiber 30 and a detector 20 comprises a closure monitor;an intrusion monitor and a first multiplexer. The monitoring fiber has afirst end and a second end and at least one detector 20 is attached tothe monitoring fiber 30. The system may also include a secondmultiplexer and one or more devices communicating along one or moveactive fibers. The active fiber has a first end and a second end andactively transmits data between the data devices. The system alsoincludes a demultiplexer. The closure monitor includes a first signalgenerator, the intrusion monitor includes a second signal generator, andthe data device includes a third signal generator.

The first signal generator of the closure monitor generates andtransmits first signal light having a first wavelength. The secondsignal generator of the intrusion monitor generates and transmits secondsignal light having a second wavelength. Subsequently, the multiplexergenerates a first multiplexed signal light by multiplexing the firstsignal light having the first wavelength and the second signal lighthaving the second wavelength.

The monitoring fiber 30 receives the transmitted first multiplexedsignal light via the first end of the monitoring fiber and reflects aportion of the first multiplexed signal light via the at least onedetector 20 to the closure monitor. Further, the monitoring fiber 30transmits a non-reflected portion of the first multiplexed signal lightvia the second end of the monitoring fiber.

The third signal generator of the data device generates and transmitsthird signal light having a third wavelength. The second multiplexer isconfigured to multiplex the non-reflected portion of the firstmultiplexed signal and the third signal light having the thirdwavelength. The data carrying third light signal is separated (orcombined) from the light signal used by the intrusion monitor at each ofthe two or more data devices (see FIG. 13).

The active fiber carries the second signal light, which passed throughthe detectors 20 and was multiplexed with the data signal. The secondsignal light returns to the intrusion monitor.

The intrusion monitor receives the second signal light having the secondwavelength as the non-reflected portion of the first multiplexed signallight. Further, the intrusion monitor monitors the non-reflected portionof the first multiplexed signal light to detect transient changes in thenon-reflected portion of the first multiplexed signal light indicativeof at least one of a vibration, a motion and a handling of at least oneof the monitoring fiber 30 and the at least one detector 20. Theintrusion monitor may also provide for intrinsic monitoring of the cable50 carrying the active fiber.

What is claimed:
 1. A system for detecting an intrusion of at least oneof a monitoring fiber and a detector comprising: a sensor having aclosure monitor and an intrusion monitor, the closure monitor includinga signal generator; the monitoring fiber having a first end and a secondend; and at least one detector attached to the monitoring fiber, whereinthe signal generator generates and transmits signal light, themonitoring fiber receives the transmitted signal light via the first endof the monitoring fiber and reflects a portion of the signal light viathe at least one detector to the closure monitor and transmits anon-reflected portion of the signal light via the second end of themonitoring fiber, and the intrusion monitor receives the transmittednon-reflected portion of the signal light, and monitors thenon-reflected portion of the signal light to detect transient changes inthe non-reflected portion of the signal light indicative of at least oneof a vibration, a motion and a handling of at least one of themonitoring fiber and the at least one detector.
 2. The system of claim1, further comprising: at least one sensor fiber having a first end anda second end, wherein the at least one sensor fiber receives thetransmitted non-reflected portion of the signal light via the first endof the at least one sensor fiber and transmits the non-reflected portionof the signal light via the second end of the at least one sensor fiber,and the intrusion monitor receives the transmitted non-reflected portionof the signal light, and monitors the non-reflected portion of thesignal light to detect transient changes in the non-reflected portion ofthe signal light indicative of at least one of a vibration, a motion anda handling of at least one of the monitoring fiber and the at least onedetector.
 3. The system of claim 1, further comprising: at least oneunused fiber having a first end and a second end, wherein the at leastone unused fiber receives the transmitted non-reflected portion of thesignal light via the first end of the at least one unused fiber andtransmits the non-reflected portion of the signal light via the secondend of the at least one unused fiber, and the intrusion monitor receivesthe transmitted non-reflected portion of the signal light, and monitorsthe non-reflected portion of the signal light to detect transientchanges in the non-reflected portion of the signal light indicative ofat least one of a vibration, a motion and a handling of at least one ofthe monitoring fiber and the at least one detector.
 4. The system ofclaim 1, further comprising: at least one sensor fiber having a firstend and a second end, and at least one unused fiber having a first endand a second end, wherein the at least one sensor fiber receives thetransmitted non-reflected portion of the signal light via the first endof the at least one sensor fiber and transmits the non-reflected portionof the signal light via the second end of the at least one sensor fiber,and the at least one unused fiber receives the transmitted non-reflectedportion of the signal light via the first end of the at least one unusedfiber and transmits the non-reflected portion of the signal light viathe second end of the at least one unused fiber, and the intrusionmonitor receives the transmitted non-reflected portion of the signallight, and monitors the non-reflected portion of the signal light todetect transient changes in the non-reflected portion of the signallight indicative of at least one of a vibration, a motion and a handlingof at least one of the monitoring fiber and the at least one detector.5. The system of claim 1, further comprising: at least one sensor fiberhaving a first end and a second end, and at least one unused fiberhaving a first end and a second end, the at least one unused fiber beinglocated proximate and along the at least one sensor fiber, wherein theat least one sensor fiber receives the transmitted non-reflected portionof the signal light via the first end of the at least one sensor fiberand transmits the non-reflected portion of the signal light via thesecond end of the at least one sensor fiber, and monitors the at leastone unused fiber, and the intrusion monitor receives the transmittednon-reflected portion of the signal light, and monitors thenon-reflected portion of the signal light to detect transient changes inthe non-reflected portion of the signal light indicative of at least oneof a vibration, a motion and a handling of at least one of themonitoring fiber and the at least one detector.
 6. The system of claim1, wherein the signal generator may be one a laser, a light emittingdiode or other broadband light source and a variable wavelength sourcesuch as a swept wavelength laser.
 7. The system of claim 1, wherein thesignal light is a continuous wave (CW) light of one of a singlewavelength and a narrow wavelength.
 8. The system of claim 1, whereinthe at least one detector may be a Fiber Bragg Grating (FBG) reflector.9. A system for detecting an intrusion of at least one of a monitoringfiber and a detector comprising: a sensor having a closure monitor andan intrusion monitor, the closure monitor including a first signalgenerator and the intrusion monitor including a second signal generator;a multiplexer; the monitoring fiber having a first end and a second end;and at least one detector attached to the monitoring fiber, wherein thefirst signal generator generates and transmits first signal light, thesecond signal generator generates and transmits second signal light, themultiplexer multiplexes the first signal light and the second signallight, the monitoring fiber receives the transmitted multiplexed signallight via the first end of the monitoring fiber and reflects a portionof the multiplexed signal light via the at least one detector to theclosure monitor, and transmits a non-reflected portion of themultiplexed signal light via the second end of the monitoring fiber, andthe intrusion monitor receives the transmitted non-reflected portion ofthe multiplexed signal light, and monitors the non-reflected portion ofthe multiplexed signal light to detect transient changes in thenon-reflected portion of the signal light indicative of at least one ofa vibration, a motion and a handling of at least one of the monitoringfiber and the at least one detector.
 10. The system of claim 9, furthercomprising: at least one sensor fiber having a first end and a secondend, wherein the at least one sensor fiber receives the transmittednon-reflected portion of the multiplexed signal light via the first endof the at least one sensor fiber and transmits the non-reflected portionof the signal light via the second end of the at least one sensor fiber,and the intrusion monitor receives the transmitted non-reflected portionof the signal light, and monitors the non-reflected portion of themultiplexed signal light to detect transient changes in thenon-reflected portion of the multiplexed signal light indicative of atleast one of a vibration, a motion and a handling of at least one of themonitoring fiber and the at least one detector.
 11. The system of claim9, further comprising: at least one unused fiber having a first end anda second end, wherein the at least one unused fiber receives thetransmitted non-reflected portion of the multiplexed signal light viathe first end of the at least one unused fiber and transmits thenon-reflected portion of the multiplexed signal light via the second endof the at least one unused fiber, and the intrusion monitor receives thetransmitted non-reflected portion of the multiplexed signal light, andmonitors the non-reflected portion of the multiplexed signal light todetect transient changes in the non-reflected portion of the signallight indicative of at least one of a vibration, a motion and a handlingof at least one of the monitoring fiber and the at least one detector.12. The system of claim 9, further comprising: at least one sensor fiberhaving a first end and a second end, and at least one unused fiberhaving a first end and a second end, wherein the at least one sensorfiber receives the transmitted non-reflected portion of the multiplexedsignal light via the first end of the at least one sensor fiber andtransmits the non-reflected portion of the multiplexed signal light viathe second end of the at least one sensor fiber, and the at least oneunused fiber receives the transmitted non-reflected portion of themultiplexed signal light via the first end of the at least one unusedfiber and transmits the non-reflected portion of the multiplexed signallight via the second end of the at least one unused fiber, and theintrusion monitor receives the transmitted non-reflected portion of themultiplexed signal light, and monitors the non-reflected portion of themultiplexed signal light to detect transient changes in thenon-reflected portion of the multiplexed signal light indicative of atleast one of a vibration, a motion and a handling of at least one of themonitoring fiber and the at least one detector.
 13. The system of claim9, wherein the first signal generator may be one of a laser, a lightemitting diode or other broadband light source and a variable wavelengthsource such as a swept wavelength laser.
 14. The system of claim 9,wherein the first signal generator is configured to generate acontinuous wave (CW) light of one of a single wavelength and a narrowwavelength.
 15. The system of claim 9, wherein the at least one detectormay be a Fiber Bragg Grating (FBG) reflector.
 16. The system of claim 9,wherein the multiplexer is one of a dense wavelength divisionmultiplexer (DWDM); a filter wavelength division multiplexer (WDM); athin film WDM; a coarse wavelength division multiplexer (CWDM); anadd/drop multiplexer, a polarization controller; and a time divisionmultiplexer (TDM).
 17. A system for detecting an intrusion of at leastone of a monitoring fiber and a detector comprising: a closure monitor,the closure monitor including a first signal generator; an intrusionmonitor; the monitoring fiber having a first end and a second end; atleast one detector attached to the monitoring fiber; a data device, thedata device including a second signal generator; a multiplexer; at leastone active fiber having a first end and a second end and activelytransmitting data; and a demultiplexer, wherein the first signalgenerator of the closure monitor generates and transmits first signallight having a first wavelength, the monitoring fiber receives thetransmitted first signal light via the first end of the monitoring fiberand reflects a portion of the first signal light via the at least onedetector to the closure monitor, and transmits a non-reflected portionof the first signal light via the second end of the monitoring fiber,the second signal generator of the data device generates and transmitssecond signal light having a second wavelength, the multiplexermultiplexes the non-reflected portion of the first signal light and thesecond signal light, the active fiber receives the transmittedmultiplexed signal light via the first end of the active fiber, andtransmits the multiplexed signal light via the second end of the activefiber, the demultiplexer separates the non-reflected portion of thefirst signal light having a first wavelength and the second signal lighthaving a second wavelength, and the intrusion monitor receives thetransmitted non-reflected portion of the first signal light, andmonitors the non-reflected portion of the first signal light to detecttransient changes in the non-reflected portion of the multiplexed signallight indicative of at least one of a vibration, a motion and a handlingof at least one of the monitoring fiber and the at least one detector.18. A system for detecting an intrusion of at least one of a monitoringfiber and a detector comprising: a closure monitor, the closure monitorincluding a first signal generator; an intrusion monitor, the intrusionmonitor including a second signal generator; a first multiplexer; themonitoring fiber having a first end and a second end; at least onedetector attached to the monitoring fiber; a second multiplexer; a datadevice, the data device including a third signal generator; at least oneactive fiber having a first end and a second end and activelytransmitting data; and a demultiplexer, wherein the first signalgenerator of the closure monitor generates and transmits first signallight having a first wavelength, the second signal generator of theintrusion monitor generates and transmits second signal light having asecond wavelength, the multiplexer generates a first multiplexed signallight by multiplexing the first signal light having the first wavelengthand the second signal light having the second wavelength, the monitoringfiber receives the transmitted first multiplexed signal light via thefirst end of the monitoring fiber and reflects a portion of the firstmultiplexed signal light via the at least one detector to the closuremonitor, and transmits a non-reflected portion of the first multiplexedsignal light via the second end of the monitoring fiber, the thirdsignal generator of the data device generates and transmits third signallight having a third wavelength, the second multiplexer generates asecond multiplexed signal by multiplexing the non-reflected portion ofthe first multiplexed signal and the third signal light having the thirdwavelength, the active fiber receives the transmitted second multiplexedsignal light via the first end of the active fiber, and transmits thesecond multiplexed signal light via the second end of the active fiber,the demultiplexer receives the transmitted second multiplexed signallight, and separates the second multiplexed signal light into the secondsignal light having the second wavelength and the third signal lighthaving the third wavelength, and the intrusion monitor receives thesecond signal light having the second wavelength of the transmittednon-reflected portion of the first multiplexed signal light, andmonitors the non-reflected portion of the first multiplexed signal lightto detect transient changes in the non-reflected portion of the firstmultiplexed signal light indicative of at least one of a vibration, amotion and a handling of at least one of the monitoring fiber and the atleast one detector.